[Richard]

Thank you for adding that you monitored the brake pressure during your trip.
That makes me feel a little better. If you had been traveling in mountainous areas then long descents could have been more problematic.

Since you are parked it may be easier to determine the big THREE.
Leak or governor or compressor. When you use shop air and disconnect the shop air, what happens? If th coach holds air then massive leak is not the issue. If the pressures on the guages drop rapidly then obviously you have a huge leak. If the brake tank guages drop at the same rate as the supply gauge then your leak is in the brake system . If the brake tanks hold but not the supply, then at least you know the leak is not in the brake system

If the pressures hold when using shop air then the next test is to disconnect shop air, bleed the air pressure down, then crank the engine. At idle, what is the max pressure the system will build after five minutes ? If you increase to 1500 rpm what is the max pressure the system will build?

If the max pressure the engine comp will build does not change with RPM then the governor may be a problem.
However if the max pressure changes with RPM then the compressor is a likely problem

[Jackflash]

Well, I got home and went out to fire up the beast, the seals were completely deflated and the door didn't even think about opening. Supply air was at 0 and the brake airs were at probably 5 or 10. Fired her up and idled for 5 minutes, all pressures were at about 45 so I raised it up to 14 or 15 hundred, another 5 minutes and the pressures were at 60 to 65. shut it down and supply pressure fell within a minute or so, experience has shown the brake pressures won't be down till tomorrow morning. The pressure increase across the 10 minute seemed pretty linear, slowing a little in the second as the pressure rose. Not sure it wouldn't have continued a similar rise at idle. Hooked it to the compressor in my garage which puts out 7 CFM at those pressures and managed to bring the supply pressure up to about 50 PSI but that's as far as it would go. Took a turn around the rv and the only sound to be heard was the air passing through the quick connect at the service port, even using the inficon. Unplugged the hose and the pressure at the supply gauge again fell within a minute or two.

[Richard]

That is some huge leak.

The problem with internet problem solving is that you don’t know exactly how someone else has done something. I am surprised the inficon didn’t hear that. But I know I had to learn how to use it, which is quite different than the advertised instructions. I have the best results by using earbuds that go into my ear and block out outside noise. With a leak that big I would set the sensitivity at low. I would walk around the coach listening with the coach earbuds while sticking the snout inside every wheel opening and thoroughly in every bay. If I didn’t hear anything, I would crib the coach to keep it from sitting on me and scoot between the drive and tag tires to get under the rear. There are a lot of
Connections in that space. And lastly I would look carefully at the slide
Seals. If one of them is ruptured you can loose a lot of air quickly.

Please keep posting on what you do and what you find. This may help someone else in the future with a similar problem

[Jackflash]

I hooked up the compressor again and thought I found a leak in the vicinity of the 12v compressor but after spraying the bubble water everywhere there wasn't a bubble to be found. I started working my way around the coach and sure enough there was a leak in the water bay, the sound was carrying all the way across toe coach. Apparently there is something going on with the valving or lines that actuate the waste dump valve. When I first found it a lotof air was escaping but wasn't all that noisey. When I actuated the valve it stopped but would return in a few minutes. Had to manually dump the tank with my portable tank (nasty job) clean everything up now I am letting everything dry out so hat I can start taking it all apart to figure out the problem. I'll lubricate and do some seal maintainance while I am in there. I'll update on the results. I also ordered a new dryER since it was leaking through the bottom valve.

[Jackflash]

Has anyone tried using a smoke leak detector before? Seemlike it would be quicker and more definitive than most methods.

[Jackflash]

has anyone ever had one of these go south?  It is the control valve for the waste dump valve.  No matter which way it is thrown, it leaks.  The right side (the side that opens the valve, I think) leaks in a wholesale fashion and the left side is a much slower leak.  The air is coming from the holes in the port on to of the unit.

[rheavn]

Just replaced one on a friend's Newell and one on mine in April 2018.  Ours were leaking in the open position.  Takes about an hour to do an R & R. Don't think that is your main leak, but if you have a bunch of those.........................................

[Richard]

Yep common problem there are threads on this forum with part numbers and sources. Good time to practice using the search engine. AKA teach you to fish instead of feeding you fish.

[folivier]

And if you're in a situation where you can't wait for parts to rebuild that valve you can always go to a hardware store and get an ice maker valve (those are usually with 1/4" ferrule fittings) and use that to stop the leak.
And in your spare parts kit you should have an assortment of air tubing and fittings so you can repair a leak as this.
But I think you have other leaks than this, but start with this and keep going.

[Jackflash]

An update on what's going on.  I installed the control valve for the dump valve and that fixed a major leak.  Found that both the fittings on the dump valve actuator were leaking a little, the lower one stopped with a little tightening but the upper one doesn't want to snug up, must be stripped.  I am now going to have to replace it anyway because when I was pulling the actuator to replace the gate my hand slipped and snapped the fitting off.  Found them on the net and they should be here this week.  Had to buy 10 so if anyone needs one give me a shout.  also found the drain valve for the wet tank and the tank near the 120v compressor leaking, replaced them, no leak.  The only other leaks I have identified at the fittings for the lines going into the left rear drive axle brake (you can barely hear it with the Inficon) and the left rear HCV.  The leak at the HCV is coming from underneath the valve not from the fittings so I guess that means a new valve is in my future.  The rig is holding pressures much longer now but is still slow to reach operating levels.  It took about 6 or 7 minutes to reach about 110 PSI from a starting point of 75 sitting at idle, never did reach its usual 120.  Still haven't installed the new governor and dryer, maybe they will help.  By the way, I give up, I have crawled all around under the beast and can't find more than 4 tanks.  I have found the two brake tanks (drained them, one was dry and the other only had a few drops of water), the wet tank and the tank at the 120v compressor.  Can't find the rectangular tanks I hear mentioned all the time or any others.  The only thing close to looking like a rectangular tank is a large tube steel cross member just forward of the drive axle air bags, it has a plug on bottom but no drain vale and I don't see any lines going to it.  I have also (after being admonished) searched the forum in every way I can think of to no avail. Can anyone give me a hint as to where the rest of these 10 or 11 tanks are?